Gastroenteritis Flashcards
campylobacter
incubation period and symptoms?
incubation period is around 3-10 days
causes inflammation of the colon and rectum - occasionally invading its way into the blood stream
source of campylobacter?
undercooked poultry, infected water and unpasteurised milk
person to person outbreaks are uncommon and a mass outbreak is due to a large group being subject to the same conditions
management of Campylobacter?
usually self limiting but give erythromycin or ciprofloxacin for 5 days if systemic symptoms develop
incubation period of salmonella enertica?
12-48 hours
pathophysiology of salmonella enertica?
inflammation of ileum and colon - bacteria then multiply in the gut and cause mucosal damage - decreasing fluid absorption and increasing fluid release
can also find its way into the blood stream rarely
symptoms of salmonella enertica?
abdominal pain, diarrhoea (sometimes bloody), vomiting
source of salmonella enertica?
undercooked poultry
management of salmonella enertica?
is usually self limiting but give ciprofloxacin if systemic symptoms start
incubation period of shigella spp.?
1-9 days
pathophysiology of shigella spp.?
invades into he mucosa of the small intestine causing inflammation but doesn’t go any further - so will never be seen in blood cultures
symptoms of shigella spp?
abdominal pain, diarrhoea (sometimes bloody and contain pus)
source of shigella?
human infection only - person to person contact
management of shigella spp.?
usually self limiting - other forms of shigella that are picked up abroad may be more severe and may need treatment with ciprofloxacin
E coli 0157 pathophysiology?
this strain of E coli produces a toxin that damages red blood cells and the kidney, causing haemolytic-uraemic syndrome - therefore increasing blood urea, red cell haemolysis and low levels of platelets within the blood
what is the toxin called in E coli and what is its mode of action?
verotoxin binds to the receptors found in renal cells, RBC and others - the toxin inhibits protein synthesis and cause cell death
source of E coli 0157?
carried as part of normal gut flora in cattle, but becomes contaminated when outside during slaughter - so caused by burgers/mince rather than steak
can also be caused by visits to farms and private untreated water sources which have been infected
management of E coli?
symptomatic and supportive treatment only - antibiotics should not be used as they can increase the levels of toxins within the blood - the bloods of a patient with E coli must be checked 1 week after to look for signs of HUS
incubation period for typhoid?
14-21 days - the infection are febrile to begin with and they circulate within the bloodstream - causing headaches, flu like symptoms and then diarrhoea 3 weeks later
symptoms of typhoid?
fever, rash on abdomen (rose spots) and diarrhoea
source of typhoid?
human infection only - spread form person to person from drinking contaminated water, and poor sanitation
management of typhoid?
antibiotics are required - resistance to ciprofolxacin is high in developing countries - azithromycin is often used
cholera incubation period?
1-9 days
pathophysiology of cholera?
organism produces a exotoxin that causes active outpouring of fluid cells from the small intestine - resulting in severe extremely watery diarrhoea (rice water stools) - causing rapid dehydration
source of cholera?
person to person spread from contaminated water/poor sanitation
management of cholera?
fluid and electrolyte replacement - antibiotics are not indicated
pathophysiology of C. Difficle?
The pathogenic c. difficle (anaerobic gram positive spore forming bacillus) dominate the flora when the normal flora of the gut has been disrupted due to antibiotics taken to cure a previous infection
what are the host risks for c difficle?
age greater than 65 immunosuppressed PPI drugs Hospitalisation/long term care previous C. Diff infection
prevention of C diff?
prompt isolation and treatment of infected individuals
controll antibiotic usage - control the 4 C’s
- clarthromycin
- co-amoxiclav
- ciprofloxaccin
- clindamycin
what GI infections are associated with ingestion of preformed toxins?
- staph aureus
- clostridium perfringens
- bacillus cereus
example of staph aureus infection?
baker touches cream to put on a cake, bacteria multiply in the cream producing a enterotoxin which is ingested by the customer
the toxin is absorbed quickly - acting directly on the vagus nerve - vomiting commences within 1-2 hours
example of clostridium perfringens infection?
(large gram positive anaerobic bacilli)
spores of of the bacteria survive cooking, then for vegetations which produce enterotoxins
heavily associated with reheated gravy
example of a bacillus cereus infection?
(large gram positive aerobic bacilli)
similar to clostridium perfringens infection in that the bacterial spore survive cooking, form vegetations then release enterotoxins
heavily associated with inadequately reheated rice
examples of short incubation times?
staph aureus and bacillus cereus
examples of medium incubation times?
salmonella and clostridium perfringens
- the medium incubation time suggest invasion of a toxin within the gut
examples of long incubation times?
campylobacter/Ecoli 0157
suggest invasions of toxin within the gut and they are often associated with bloody diarrhoea
examples of parasites that cause GI infections?
- cryptosporidium
- giardia lamblia
- enetrobius vermicularis
characteristics of and giadia lamblia cryptosporidium?
‘protozal’ – single organism infection
infection occurs when cysts are ingested and hatch into trophozoites that invade cells within the small intestine
source and symptoms symptoms of cryptosporidium?
domestic animals (calves) person to person spread as well as contaminated water and swimming pools
diarrhoea that is particularly severe in patients suffering from HIV
source, symptoms and treatment of giardia lamblia?
person to person spread - associated with contaminated water supplies
diarrhoea, malabsorption syndrome, anorexia, abdominal pain, flatulence
oral metronidazole
characteristics of a enterbius vermicularia “threadworm” infection?
tiny white worms that look like small pieces of thread when passed in stools – seen in school children and will often infect several members of the family
pathophysiology if enetrbius vermicularia?
eggs are ingested, hatch in the intestine and live in the caecum and colon, females then come out to lay eggs in the perianal area at night, child scratches bottom and then puts fingers in mouth
symptoms – perianal itch, worms seen in stool
source and management of “threadworm” infection?
human to human contact only - poor hygiene
oral mebendazole - often has to be used to treat the whole family
